My Passport formatted for Mac, not recognized by second Mac

WD External Drives External Drives for Mac
1

Formated 2tb my passport drive with “WD Drive Utilities” for Mac.  Copied itunes library to it.  Works fine.

I then connected the same drive to a 2nd macmini–was not recognized even after installing WD Drive

utilities for Mac.  Connected drive back to 1st Mac–works fine. Why does 2nd Mac not see t he drive>

                                                           Martin_r10

2

Hi, the Mac mini might not be providing enough energy for the passport to work correctly, avoid using USB extension cables or USB hubs. Try calling tech support to see if you can get a power booster cable. 

http://support.wdc.com/contact/contact.asp?lang=en